After a candidate's forum at a Winchester, Va., hotel Friday, two young campaign workers for Democrat Judy Feder, who is challenging 14-term incumbent Rep. Frank R. Wolf (R) in Northern Virginia, learned this the hard way.

Armed with a video camera, the Feder workers followed Wolf, his wife and a congressional staffer down the stairs and into the lobby to pepper Wolf with questions that they say he has evaded over the course of the campaign.

That's when Wolf's 83-year-old staffer whacked the videographer with a metal cane.

"Sir, please don't!" yelled the videographer, Matt Kent, 22, a field organizer for Feder's campaign, in the video, which the campaign posted on YouTube and on a Democratic blog over the weekend.

Yesterday morning, Wolf's campaign apologized for the actions of Ben Dutton, a former Winchester city council member who has worked for Wolf since 1992. But the congressman's reelection team also condemned the tactics employed by Feder's campaign, which they said was trying to goad Wolf into a hostile reaction with aggressive and incessant questioning.

"The campaign apologizes if Ben used poor judgment and hit him with his cane," said Dan Scandling, a Wolf campaign spokesman. But, he added, "the whole thing was provoked. It was a setup."

Ever since Virginia politician George Allen's political aspirations were sunk two years ago with the help of an online video, candidates have sent workers to shadow their opponents with cameras in the hopes of capturing a gaffe and plastering it across the Internet.

The tactic, called "tracking," has been criticized by politicians who have been the subject of it. Allen is widely believed to have lost his Senate race against James Webb in 2006 after he was caught on tape using an ethnic slur against a young Webb volunteer who had been tracking the then-incumbent senator.

Last year, Maine Sen. Susan Collins (R) made headlines when she demanded that her Democratic opponent call off his tracker. This year, independent activists and some associated with Democratic campaigns in Virginia have engaged in the practice too.

A frequent target has been Rep. Virgil Goode (R), who is fighting a challenge from Democrat Tom Perriello on Nov. 4.

"Somebody is usually at every campaign stop," Goode said. "I think they just travel around to try to spin something their way."